Track condition monitoring device, track condition monitoring system and track condition monitoring method

ABSTRACT

A track condition monitoring device track condition monitors a state of a track on which a railroad car runs. The track condition monitoring device includes processing circuitry configured to acquire track displacement data which includes first data associated with second data, the first data indicating a position of the track displaced by a track displacement, and the second data indicating a longitudinal level of the track displacement at the position; and calculate an index value indicating the state of the track in an evaluation target section of the track based on the track displacement data, wherein the position is in the evaluation target section of the track.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a bypass continuation of PCT/JP2020/046796, filed on Dec. 15, 2020, the entire contents of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a technique for monitoring a state of a track.

SUMMARY

In accordance with the present disclosure, a track condition monitoring device monitors a state of a track, the track condition monitoring device comprises processing circuitry configured to acquire track displacement data which includes first data associated with second data, the first data indicating a position of the track displaced by a track displacement, and the second data indicating a longitudinal level of the track displacement at the position; and calculate an index value indicating the state of the track in an evaluation target section of the track based on the track displacement data, wherein the position is in the evaluation target section of the track.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 An explanation diagram illustrating an overall configuration of a track condition monitoring system according to an embodiment.

FIG. 2 An explanation diagram illustrating an example of a proceeding state of a displacement of a track.

FIG. 3 A block diagram illustrating an example of a position-related information acquisition unit and a track displacement position acquisition unit.

FIG. 4 A flow chart illustrating a processing example of a processing unit in the track condition monitoring device.

FIG. 5 A diagram illustrating an example of a waveform based on track displacement data.

FIG. 6 A diagram illustrating an example of a change in an index value with respect to an elapsed time.

FIG. 7 A diagram illustrating an example of a change in a standard deviation with respect to an elapsed time.

FIG. 8 A diagram illustrating an example of a change in a fractal dimension with respect to an elapsed time.

FIG. 9 A flow chart illustrating a processing example of the processing unit according to a modification example.

FIG. 10 A diagram illustrating an example of a change in an index value with respect to a time including a future.

FIG. 11 A diagram illustrating an example of a track condition display image.

FIG. 12 A diagram illustrating another example of the track condition display image.

DETAILED DESCRIPTION

When a railroad car repeatedly passes a track, a track displacement proceeds. When the track displacement proceeds, a maintenance operation of the track is performed as necessary. Thus, evaluation of a track condition by an appropriate index value is required.

The inventor of the present disclosure has recognized that conventional track management systems express the track condition by a standard deviation, and there is a problem that a value of the standard deviation varies widely for each measurement. Further, the track condition can be expressed by a fractal dimension obtained by a fractal analysis, which has a similar problem because a value of the fractal dimension varies for each measurement in a manner similar to the standard deviation.

The inventor has developed technologies as explained in the present disclosure is to address these problems, so as to reduce variation of an index value expressing a track condition in each measurement.

In an exemplary implementation, a track condition monitoring device monitors a state of a track on which a railroad car runs, the track condition monitoring device including a processing unit calculating at least one index value indicating a state of a track, wherein the processing unit calculates a value corresponding to a length of the track caused by a track displacement in an evaluation target section as the index value based on track displacement data in which data of a track position caused by the track displacement is associated with data of a position of the track in a longitudinal direction.

According to the track condition monitoring device, the value corresponding to the length of the track caused by the track displacement in the evaluation target section is set to the index value indicating the track condition, thus variation of the index value is reduced, and the track condition can be predicted with high accuracy.

In another exemplary implementation, a track condition monitoring system includes: a track condition monitoring device, a position-related information acquisition unit provided to the railroad car, and acquiring track position data capable of specifying a position of the track in a longitudinal direction; and a track displacement position acquisition unit provided to the railroad car, and acquiring a displacement position of the track caused by the track displacement.

According to the track condition monitoring system, the track position data and the position data in which the track displacement is observed are collected when the railroad car runs on the track, thus the track displacement data can be generated.

In another exemplary implementation, a track condition monitoring method is for monitoring a state of a track on which a railroad car runs, the track condition monitoring method including: (a) acquiring track displacement data in which data of a track position caused by a track displacement is associated with data of a position of the track in a longitudinal direction; and (b) calculating a value corresponding to a length of the track caused by the track displacement in an evaluation section as at least one index value indicating a state of a track based on the track displacement data.

According to the track condition monitoring method, the value corresponding to the length of the track caused by the track displacement in the evaluation target section is set to the index value indicating the track condition, thus variation of the index value is reduced, and the track condition can be predicted with high accuracy.

Described hereinafter are a track condition monitoring device, a track condition monitoring system, and a track condition monitoring method according to an embodiment. FIG. 1 is an explanation diagram illustrating an overall configuration of a track condition monitoring system 30.

An example of a track 10 monitored by the present system 30 is described. The track 10 is a road guiding a railroad car 20 along a predetermined path. The track 10 herein includes two rails 12. The two rails 12 may be laid in parallel with each other over the ground via ties and the like. The track may be a track including only one rail guiding the railroad car, as in monorails. The track may be provided at a location above the ground using a viaduct and the like. The track may be provided in a tunnel bored underground.

The railroad car 20 includes a body 22 and bogies 24. The bogies 24 each include a truck frame 25 and wheels 25W. The wheels 25W are rotatably supported in left and right portion of the truck frame 25 via an axle. A part supporting the axle is also referred to as an axle box. A direction of run and a direction of backing of the railroad car 20 are also respectively referred to as a forward direction and a backward direction in the present embodiment. Left and right sides are referred to left and right sides as viewed in the direction of run from the railroad car 20 in some cases. A side to which gravity is applied in a direction of gravity is also referred to as a lower side, and a side opposite the lower side is also referred to as an upper side. The right and left wheels 25W run on the two rails 12 while being guided by the rails 12. The bogies 24 support the body 22 from below. The bogies 24 run on the track 10, so that the railroad car 20 including the body 22 runs along the track 10. The railroad car 20 may be any of an electric train, a locomotive and a freight car of a freight train, and a locomotive and a passenger car of a passenger train as long as it runs on the track 10. The freight train or the passenger train may be a trailing car towed by the locomotive, or may be a motive power car having its motive power. The locomotive may be an electric locomotive, or may be an internal combustion locomotive, such as a diesel locomotive. The railroad car 20 may be a commercial car for transporting a human or a baggage, or may also be a business car for monitoring a track condition.

As illustrated in FIG. 2 , when the railroad car 20 repeatedly runs on the track 10, a displacement of the track 10 proceeds. For example, FIG. 2 illustrates that a longitudinal level displacement of the track 10 proceeds in accordance with an elapse of times T1, T2, and T3. When the displacement of the track 10 proceeds, shaking of the railroad car 20 during running increases, thus a maintenance operation for reducing the displacement of the track 10 is performed.

The maintenance of the track 10 is performed by a dedicated track maintenance car, for example. However, the track maintenance car is expensive, and a distance in which the maintenance can be performed at one time is limited to approximately 1 km. Thus, it is desired that a limited number of cars is efficiently operated. When a long-term transition of the track condition can be predicted with accuracy as high as possible while accurately grasping the track condition, planning of a track maintenance plan of the track 10 can be efficiently performed. The index value expressing the track condition is hardly varied in each measurement by the track condition monitoring device, a track condition monitoring system, and a track condition monitoring method described in the present embodiment, and the track condition can be accurately grasped.

As illustrated in FIG. 1 , the track condition monitoring system 30 is a system for monitoring a track condition, and includes a position-related information acquisition unit 32, a track displacement position acquisition unit 40, and a track condition monitoring device 50.

The position-related information acquisition unit 32 and the track displacement position acquisition unit 40 are provided to the railroad car 20 described above. The track condition monitoring device 50 is provided to a management base 14. The management base 14 is provided at a different location from the railroad car 20. For example, the management base 14 is architecture provided on the ground to monitor the railroad car 20. The position-related information acquisition unit 32 and the track displacement position acquisition unit 40 are communicably connected to the track condition monitoring device 50 via a communication network 16. Accordingly, an acquisition result by the position-related information acquisition unit 32 and an acquisition result by the track displacement position acquisition unit 40 are transmitted to the track condition monitoring device 50 via the communication network 16. The communication network 16 may be a wired or wireless communication network, and may be a combination of the wired and wireless communication networks. The communication network 16 may be a public communication network or a communication network using a dedicated line.

The position-related information acquisition unit 32 acquires position data capable of specifying a position of the track 10 in a longitudinal direction. The position of the track 10 in the longitudinal direction may be a position (for example, kilometrage) based on a fixing position in the longitudinal direction of the track 10 (for example, starting point of a railroad or a certain station), or may also be a position based on an optional position in the longitudinal direction of the track 10. The position data may be information directly indicating a position of the track 10 in the longitudinal direction, or may also be information capable of obtaining a position of the track 10 in the longitudinal direction via calculation processing. For example, the position-related information acquisition unit 32 may include a rotation number sensor detecting the number of rotations of the wheels, and output a running distance from a certain position based on the detection result of the rotation number sensor or a speed at constant time interval. For example, the position-related information acquisition unit 32 may include an acceleration sensor detecting an acceleration rate in the direction of run of the railroad car 20, and output an acceleration rate based on the detection result of the acceleration sensor or a speed. For example, the position-related information acquisition unit 32 may include a global positioning system (GPS) receiving unit, and output latitude-longitude information acquired by a receiving signal from the GPS receiving unit or a position in the longitudinal direction of the track 10 based on the latitude-longitude information.

The track displacement position acquisition unit 40 acquires track position data caused by a track displacement. The displacement of the track 10 may be a position in any direction indicating a displacement state of the track 10. For example, the track displacement of the track 10 may be a longitudinal level displacement or lateral alignment displacement. The longitudinal level displacement is a vertical displacement in the longitudinal direction of the rail 12, and is a vertical displacement of a top surface of the rail 12, for example. The lateral alignment displacement is a horizontal displacement in the longitudinal direction of the rail 12, and is a horizontal displacement of a head part side surface of the rail 12, for example. In the description of the present embodiment, the displacement of the track 10 is mainly the longitudinal level displacement. The displacement of a portion to be detected in the track 10 may be acquired based on anteroposterior portions of the portion to be detected. For example, the displacement of the track 10 may be measured by a versine method (for example, 10 m-chord versine method) or an inertial mid-chord offset method (described hereinafter).

When the railroad car 20 runs, the position-related information acquisition unit 32 acquires the position data capable of specifying the position of the track 10 in the longitudinal direction, and the track displacement position acquisition unit 40 acquires the position of the track 10 caused by the track displacement in association with the position based on the position data.

A more specific example of the position-related information acquisition unit 32 and the track displacement position acquisition unit 40 is described with reference to FIG. 3 .

In the example in FIG. 3 , a speed sensor 32 a is provided to the railroad car 20 as the position-related information acquisition unit 32. The speed sensor 32 a is a sensor detecting a speed of the railroad car 20. The speed sensor 32 a may be a tachometer generator incorporated into the railroad car 20. A speed of railroad car at regular time intervals detected by the speed sensor 32 a may be outputted as the position data acquired by the position-related information acquisition unit 32. A running distance of the railroad car 20 is obtained by integrating the speed of railroad car, and the position of the track 10 in the longitudinal direction can be specified by the running distance.

A gyro sensor 42 and a distance sensor 44 are provided to the railroad car 20 as the track displacement position acquisition unit 40. The gyro sensor 42 as a movement detection unit outputs an angular speed detection signal corresponding to an angular speed of the railroad car 20 and an acceleration detection signal corresponding to an acceleration rate of the railroad car 20. An acceleration sensor outputting an acceleration detection signal corresponding to an acceleration rate of the railroad car 20 may be provided in addition to a gyro sensor outputting an angular speed detection signal corresponding to an angular speed of the railroad car 20.

A signal corresponding to a movement of the railroad car 20 is outputted from the gyro sensor 42 described above when the railroad car 20 runs on the track 10. The movement of the railroad car 20 in a ground space where the railroad car 20 is located is calculated by the output from the gyro sensor 42, and the position of the railroad car 20 in the ground space can be thereby estimated.

The distance sensor 44 is an example of a track relative position measurement unit measuring a relative position of the track 10 with respect to the railroad car 20, and outputting a signal corresponding to the relative position. Various types of distance sensor such as a laser sensor, an ultrasonic sensor, and an optical sensor may be used as the distance sensor 44. The distance sensors 44 are provided on right and left sides of each of the right and left rails 12. Each distance sensor 44 detects a height position of a top surface of the rail 12 with respect to the railroad car 20.

The example of the measurement unit detecting the position of the track 10 with respect to the railroad car 20 is not limited to the example described above. A shape measurement device by an optical cutting method may be used as the track relative position measurement unit, for example. The shape measurement device using the optical cutting method is a device irradiating the rail 12 with a slit light source, taking an image including a slit light in the image, and calculating a coordinate position of the surface of the rail 12 based on the position of the slit in the taken image.

The speed sensor 32 a and the distance sensor 44 described above may be provided in any position of the railroad car 20. For example, the speed sensor 32 a and the distance sensor 44 may be provided in the body 22 or the bogie 24. The speed sensor 32 a and the distance sensor 44 may be provided to a common portion of the railroad car 20 indicating the same movement, for example, or to a common portion of either the body 22 or the bogie 24. In this case, the speed sensor 32 a and the distance sensor 44 move in the similar manner with respect to the track 10, thus the position of the rail 12 with respect to the ground space where the railroad car 20 is located can be acquired more accurately. The track displacement position acquisition unit 40 may acquire the position of the rail 12 with respect to the railroad car 20 as the position of the track 10.

As illustrated in FIG. 1 and FIG. 3 , a data collection device 26 and a communication device 28 are provided to the railroad car 20. The data collection device 26 is made up of a processor such as a central processing unit (CPU) and a computer including a storage device, for example. The output from each of the position-related information acquisition unit 32 and the track displacement position acquisition unit 40 described above is given to the data collection device 26. The data collection device 26 temporarily stores acquisition data 27 based on the output thereof.

The communication device 28 includes a communication circuit which can be connected to the communication network 16. The communication device 28 is a wireless communication device, for example. The data collection device 26 transmits the acquisition data 27 via the communication device 28. The acquisition data 27 may be transmitted in real time, or may be transmitted at predetermined time intervals or at predetermined running distance intervals.

The position-related information acquisition unit 32 and the track displacement position acquisition unit 40 described above may be provided to the plurality of railroad cars 20. In this case, the acquisition data 27 is acquired every time each railroad car 20 runs. The acquired data 27 is wirelessly transmitted from the railroad car 20.

In the present embodiment, the transmitted acquisition data 27 is stored in a data server 18 via the communication network 16. The data server 18 is made up of a computer including a processor such as a CPU, a storage device 19, and the like. The data server 18 receives the acquisition data 27 transmitted from the railroad car 20 via the communication network 16, and stores the plural pieces of acquisition data 27 as collection data 19 a in the storage device 19. Data including the acquisition data 27 at a different time acquired by the same or different railroad car 20 is stored as the collection data 19 a by the data server 18.

The track condition monitoring device 50 monitors a state of the track 10 described above on which the railroad car 20 runs. The track condition monitoring device 50 is communicably connected to the data server 18 described above. The data server 18 may be provided in the same position as the track condition monitoring device 50, or may also be provided in a different position. The track condition monitoring device 50 and the data server 18 may be connected via the communication network 16 described above, or may also be connected via a dedicated communication line. The present embodiment indicates an example that an acquisition result by the position-related information acquisition unit 32 and an acquisition result by the track displacement position acquisition unit 40 are provided to the track condition monitoring device 50 via a communication network and the data server 18. It is also applicable that the data server 18 is omitted, and the collection data 19 a is directly stored in the track condition monitoring device 50.

The track condition monitoring device 50 is made up of a computer including a processor 52 such as a CPU, a storage device 56, and a communication device 54, for example. The communication device 54 includes a communication circuit, and the track condition monitoring device 50 is communicably connected to the data server 18 via the communication device 54. As described above, the communication device 54 may be a dedicated communication device connected to only the data server 18, or may also be a communication device connected to the communication network 16. The communication device 54 is an example of an input unit to which a signal indicating position data capable of calculating the position of the track 10 in the longitudinal direction and a signal indicating the position of the track caused by the displacement of the track 10 are inputted.

The functionality of the elements disclosed herein may be implemented using circuitry or processing circuitry which includes general purpose processors, special purpose processors, integrated circuits, ASICs (“Application Specific Integrated Circuits”), conventional circuitry and/or combinations thereof which are configured or programmed to perform the disclosed functionality. Processors are considered processing circuitry or circuitry as they include transistors and other circuitry therein. The processor may be a programmed processor which executes a program stored in a memory. In the disclosure, the circuitry, units, or means are hardware that carry out or are programmed to perform the recited functionality. The hardware may be any hardware disclosed herein or otherwise known which is programmed or configured to carry out the recited functionality. When the hardware is a processor which may be considered a type of circuitry, the circuitry, means, or units are a combination of hardware and software, the software being used to configure the hardware and/or processor. In this disclosure, the processor 52 includes a calculation circuit. The processor 52 is an example of a processing unit calculating an index value indicating a track condition. The processor 52 may perform processing according to a modification example described hereinafter.

The storage device 56 is made up of a non-volatile storage device such as a hard disk drive (HDD) and a solid-state drive (SSD). The storage device 56 stores a program 56 a, collection data 56 b, track displacement data 56 c, and index data 56 d. Processing for the processor 52 to achieve a function as the processing unit is described in the program 56 a. Accordingly, the processor 52 executes the processing described in the program 56 a stored in the storage device 56, for example, thus the processing as the processing unit calculating an evaluation value is executed. The number of the processors 52 may be one, or the plurality of processors 52 are also applicable. The processors 52 may be incorporated into one computer. It is also applicable that the processors 52 are incorporated into computers, and the computers separately perform processing as the processing units calculating the evaluation value. The collection data 56 b is data corresponding to the track 10 be evaluated in the collection data 19 a stored in the data server 18. The track displacement data 56 c is data in which data of the track position caused by the displacement of the track 10 is associated with data of the position of the track 10 in the longitudinal direction, and is acquired based on the collection data 19 a. The index data 56 d is data in which an index value for each evaluation target section in the track 10 to be evaluated is associated, and can be generated based on the track displacement data 56 c.

The track condition monitoring device 50 may include an input unit 58 receiving instructions from a user on the track condition monitoring device 50. The input unit 58 may be a key board, a mouse, a touch panel including switches, for example.

The track condition monitoring device 50 may include a display device 59 displaying various types of information by the track condition monitoring device 50. The display device 59 may be a liquid crystal display device or an organic electro-luminescence (EL) display device, for example. A display device provided to a smartphone or a tablet terminal, for example, may be used as the display device 59.

A processing example as the processing unit in the track condition monitoring device 50 is described with reference to a flow chart illustrated in FIG. 4 .

In Step S1, data of an evaluation target track in the collection data 19 a stored in the data server 18 is acquired. The acquired data is stored as the collection data 56 b in the storage device 56. For example, when the plurality of railroad cars 20 run on various types of tracks, the acquisition data 27 associated with the various types of tracks is transmitted to the data server 18. Accordingly, the acquisition data 27 acquired in a different time is stored for the various types of tracks. When a state of a certain track is evaluated, a group of acquisition data 27 associated with the track to be evaluated is transmitted to the track condition monitoring device 50 from the data server 18, and is stored as the collection data 19 a.

In subsequent Step S2, the track displacement data 56 c is calculated based on the collection data 19 a, and is stored in the storage device 56. For example, assumed is a case where the collection data 19 a (acquisition data 27) is speed data, an angular speed and acceleration data of the railroad car 20, and longitudinal level position data of the track 10 in each predetermined sampling cycle. In this case, the speed data from a certain reference time is integrated to calculate a running distance of the railroad car 20 at each sampling timing from the reference time. The longitudinal level position of the track 10 by the longitudinal level displacement is calculated by the inertial mid-chord offset method based on the angular speed and acceleration data of the railroad car 20 and the longitudinal level position data of the track 10 with respect to the railroad car 20 in each sampling timing. In the inertial mid-chord offset method, the position of the railroad car 20 in the ground space is calculated based on the angular speed and acceleration data of the railroad car 20 in accordance with principle of inertia. The longitudinal level position of the track 10 in the ground space is calculated based on the position of the railroad car 20 in the calculated ground space and the longitudinal level position data of the track 10 with respect to the detected railroad car 20. Calculated is a value indicating the longitudinal level displacement of the track 10 corresponding to the versine method (for example, 10 m-chord versine method) from the longitudinal level position of the track 10 in the calculated ground space.

In this manner, the running distance of the railroad car 20 from a predetermined reference position and the longitudinal level displacement of the track 10 in each sampling timing are calculated. Then, the data calculated in such as manner is converted into data of longitudinal level displacement of the track 10 with respect to the running distance from a certain reference position as a start point. Accordingly, generated is the track displacement data 56 c in which data of the track position caused by the displacement of the track 10 is associated with data of the position of the track 10 in the longitudinal direction. When there is the other collection data 19 a (acquisition data 27) regarding the track 10 to be evaluated, the track displacement data 56 c is generated in the similar manner based on the other collection data 19 a (acquisition data 27). The generated track displacement data 56 c is stored in the storage device 56. Thus, the plural pieces of track displacement data 56 c based on the plural pieces of collection data 19 a each acquired in different times may be stored in the storage device 56 in some cases.

Different processing may be performed depending on a type of data included in the collection data 19 a in Step S2 in some cases. For example, when the collection data 19 a includes the running distance as the position data, the processing of calculating the running distance of the railroad car 20 described above may be omitted. When the collection data 19 a includes latitude-longitude data in each sampling timing based on a GPS signal as the position data, processing of specifying the position of the track 10 in the longitudinal direction in each sampling timing may be performed based on the latitude-longitude data and preset route data of the track 10.

It is not necessary to acquire the track displacement position by the versine method or the inertial mid-chord offset method, for example. It is sufficient that the track displacement position is a value capable of evaluating proceeding of displacement of the track 10, and the position of the track 10 based on the running railroad car 20 is also applicable.

In subsequent Step S3, data corresponding to the evaluation target section in the track 10 to be evaluated is extracted from the track displacement data 56 c. That is to say, the track 10 to be evaluated is divided at certain intervals (for example, 100 m) appropriate to manage the maintenance and managed for each of the plurality of evaluation target sections. In Step S3, one piece of data in the plurality of evaluation target sections is extracted. That is to say, data corresponding to the evaluation target section in the track displacement data 56 c is extracted. This data may be expressed by a data column in which a position coordinate of the track 10 in the longitudinal direction and a longitudinal level displacement coordinate of the track 10 are grouped. The data may be expressed as {(x₀, y₀), (x₁, y₁), . . . , (x_(n), y_(n))}, for example. The extraction data regarding one evaluation target section may include plural pieces of data based on the acquisition data 27 acquired in a different time. The evaluation target sections may be set as sections mutually excluded in the track 10, or may also be set as sections partially overlapped with each other. The evaluation target sections may be section having the same length or a length different from each other. The evaluation target sections are described based on an assumption that they are set as sections having the same length mutually excluded in the track 10.

In subsequent Step S4 and Step S5, a value corresponding to the length of the track 10 caused by the displacement of the track 10 in the evaluation target section is calculated as the index value based on the track displacement data 56 c. Herein, the length of the track 10 caused by the displacement of the track 10 in the evaluation target section is an actual length of the track 10 in the evaluation target section. This length of the track 10 increases as the track 10 is displaced to be undulating with respect to a particular route. For example, in a case where the track 10 forms a straight line at a time T1 in the example illustrated in FIG. 2 , when irregularity of the track 10 proceeds at a time T2, the length of the track 10 increases, and when irregularity of the track 10 further proceeds at a time T3, the length of the track 10 increases. The length of the track 10 depends on not only a size of concave or convex of the track 10 but also a repetition period of concave and convex. That is to say, the length of the track 10 is large when the size of concave or convex of the track 10 is large, and is large when the repetition period of convex and concave is short. Shaking of the railroad car 20 increases in any of the case where the size of concave or convex of the track 10 increases and the case where the repetition period of concave and convex decreases. Thus, the value corresponding to the length of the track 10 caused by the displacement of the track 10 in the evaluation target section is appropriate as the evaluation value for considering necessity of the maintenance of the track 10. Such a value corresponding to the length of the track 10 may be considered as a value that a positive or negative correlative relationship is established so that the value increases or decreases when the length thereof increases.

In the present embodiment, a waveform length of the displacement of the track 10 in the evaluation target section is calculated based on the extracted track displacement data 56 c in Step S4. With reference to FIG. 5 , when the extracted track displacement data 56 c is expressed by a coordinate system having a lateral axis indicating a position of the track in the longitudinal direction and a vertical axis indicating a longitudinal level displacement position, the track displacement data 56 c is expressed as a waveform changed to be longitudinally undulating as the position of the track in the longitudinal direction increases, for example. A curved line smoothly connecting each coordinate is illustrated by a dashed-two dotted line in FIG. 5 . This dashed-two dotted line is considered to indicate the longitudinal level displacement of the track 10. A waveform length of the displacement of the track 10 may be obtained by a total sum of a straight line connecting each coordinate described above. A waveform length L of the displacement of the track 10 is calculated by a subsequent number 1, for example, based on a premise of the data column described above.

$\begin{matrix} {L = {\sum\limits_{i = 1}^{n}\sqrt{\left( {x_{i} - x_{i - 1}} \right)^{2} + \left( {y_{i} - y_{i - 1}} \right)^{2}}}} & \left\lbrack {{Expression}1} \right\rbrack \end{matrix}$

The waveform length L may be obtained as an approximated value.

In subsequent Step S5, a length Li of the track 10 is subtracted from the waveform length L. The length Li of the track 10 is a length in a case where no track displacement described above occurs. A length Li is calculated by a value in which an x coordinate of initial data is subtracted from an x coordinate of final data in the data column, that is to say, x_(n)−x₀. A value in which the length Li of the track 10 is subtracted from the waveform length L is defined as the index value.

In subsequent Step S6, the calculated index value is stored as the index data 56 d in the storage device 56. When the plural pieces of data based on the plural pieces of track displacement data 56 c are included in the evaluation target section, the index value is calculated for each data. The calculated plurality of index values are associated with the time at which the data thereof is acquired, and is stored as the index data 56 d in the storage device 56. The time at which the data is acquired may be set based on any data included in the data column. The description hereinafter is based on a premise that there are a plurality of index values of different times.

In subsequent Step S7, presence or absence of the other evaluation target section which has not been evaluated is determined in the track 10 to be evaluated. When there is the other evaluation target section which has not been evaluated, the processing returns to Step S3, and the processing subsequent to Step S3 is executed for the other evaluation target section. The processing from Step S3 to Step S6 is repeated on the plurality of evaluation target sections until the evaluation is finished. Accordingly, the index value is calculated for each of the plurality of evaluation target sections included in the track 10 to be evaluated.

When it is determined that there is no other evaluation target section in Step S7, the processing proceeds to Step S8. In Step S8, the track condition based on the index value is displayed in the display device 59.

FIG. 6 illustrates a display example in the display device 59. The display example includes a track condition display image 59A indicating the track condition. The track condition may be a current state, or may also be a predicted future state. The track condition display image 59A may include an image 59A1 indicating a change of the index value with respect to an elapsed time. More specifically, displayed is the image 59A1 in which a plurality of index values of each of the times are plotted in a graph having a lateral axis indicating an elapsed time (the date in FIG. 6 ) with respect to a reference time of predetermined processing and a vertical axis indicating the evaluation value (in FIG. 6 , the evaluation value is normalized to set a maximum value to 1). In FIG. 6 , the evaluation value for the right and left rails 12 is displayed, thus the index values are separated into upper and lower groups. The index values gradually increases with time in each of the right and left rails 12. The maintenance operation is performed on the track 10, thus the index value temporarily decreases, but gradually increases again with time.

In this manner, according to the present embodiment, the value corresponding to the length of the track 10 caused by the displacement of the track 10 in the evaluation target section is set to the index value indicating the track condition. The length of the track 10 caused by the displacement of the track 10 does not excessively reflect variation of a concave-concave displacement of the track 10 in the longitudinal direction, but reflects a total amount of the concave-concave displacement. Thus, the track condition caused by the displacement of the track 10 is appropriately evaluated by the index value which is hardly varied. A prediction accuracy of the index value in a future is improved by the index value which is less varied, and as a result, a maintenance plan can be appropriately generated.

For example, FIG. 7 illustrates the track condition in which the data indicating the track condition illustrated in FIG. 6 is evaluated by a standard deviation, and FIG. 8 illustrates the track condition in which the data thereof is evaluated by a fractal analysis.

The standard deviation and the fractal dimension are normalized in FIG. 7 and FIG. 8 . “Normalization” herein indicates that the index value of the data acquisition period is normalized so that a maximum value thereof is set to 1 and a minimum value thereof is set to 0 without consideration of the left rail and the right rail. It is understood from any of FIG. 6 to FIG. 8 that the index value gradually increases with time. However, it is understood that the variation of the index value in FIG. 6 is clearly smaller than that of the standard deviation in FIG. 7 and that of the fractal dimension in FIG. 8 . Thus, it is understood that the index value corresponding to the length of the track 10 caused by the displacement of the track 10 in the evaluation target section is hardly varied, and is appropriate to appropriately evaluate the track condition caused by the displacement of the track 10.

The position-related information acquisition unit 32 and the track displacement position acquisition unit 40 are provided to the railroad car 20. Thus, the position data and the displacement of the track 10 is easily acquired by running of the railroad car 20 on the track 10. Accordingly, the track displacement data 56 c is generated by running of the railroad car 20, and furthermore, the index value described above is calculated, thus the state of the track 10 is can be easily evaluated.

The track condition monitoring device 50 including the processor 52 as the processing unit described above is provided to the management base 14, and an acquisition result by the position-related information acquisition unit 32 and an acquisition result by the track displacement position acquisition unit 40 are transmitted to the track condition monitoring device 50 via the communication network 16. Thus, the track condition can be monitored in the track condition monitoring device 50 located away from the railroad car 20.

An acquisition result by the position-related information acquisition unit 32 and an acquisition result by the track displacement position acquisition unit 40 at different times are transmitted to the data server 18 or the track condition monitoring device 50 via the communication network 16, and the track displacement data 56 c based those pieces of data is stored in the data server 18 or the track condition monitoring device 50, change of the track condition is easily grasped based on the stored data. Accordingly, the analysis for a future state prediction is easily performed.

The longitudinal level displacement of the track 10 has influence on a vertical vibration of the railroad car 20 running on the track 10. The processor 52 as the processing unit in the present embodiment calculates the value corresponding to the length of the track 10 caused by the longitudinal level displacement of the track 10 in the evaluation target section as the index value indicating the track condition based on the track displacement data 56 c. The state of the longitudinal level displacement of the track 10 easily having influence on the vertical vibration of the railroad car 20 is properly evaluated.

The processor 52 as the processing unit may calculate the value corresponding to the length of the track 10 caused by the lateral alignment displacement of the track 10 in the width direction in the evaluation target section as the index value indicating the track condition. In this case, it is sufficient that the track displacement position acquisition unit 40 detects horizontal displacement of the rail 12.

The processing of calculating the index value includes processing of calculating a waveform length of the displacement of the track 10 in the evaluation target section based on the track displacement data 56 c. The calculation processing of the waveform length of the displacement of the track 10 can be calculated based on a geometric positional relationship, for example. Thus, the index value can be simply calculated with a small calculation amount compared with the case of obtaining the fractal dimension, for example.

The index value may be the waveform length L itself. The index value may also be a value obtained by performing predetermined calculation processing on the waveform length L.

For example, as described above, the processing of obtaining the index value may include the processing of subtracting the length Li of the track 10 from the waveform length L described above. A value obtained by subtracting the length Li of the track 10 from the waveform length L reflects a degree of change of an actual track 10 from a track 10. Thus, a user can easily imagine a deviation of the actual track 10 from the index value based on the value obtained by subtracting the length Li of the track 10 from the waveform length L. The index value may be the value itself obtained by subtracting the length Li of the track 10 from the waveform length L or a value obtained by performing the other calculation.

The index value may be a value obtained by dividing the waveform length L by a distance in the evaluation target section, for example. In this case, a magnitude of the deviation of the track 10 can be easily evaluated in the plurality of evaluation target sections each having a different distance.

The value obtained by subtracting the length Li from the waveform length L described above may be calculated by integration of subsequent Expression 2.

$\begin{matrix} \begin{matrix} {{\sqrt{x^{2} + {\Delta{y}^{2}}} - x} = {{x\sqrt{1 + \frac{\Delta y^{2}}{x^{2}}}} - x}} \\ {\simeq {{x\left( {1 + \frac{\Delta y^{2}}{2x^{2}}} \right)} - x}} \\ {= \frac{\Delta y^{2}}{2x}} \end{matrix} & \left\lbrack {{Expression}2} \right\rbrack \end{matrix}$

In Expression 2, x is a distance between adjacent samples, and Δy is a different of the longitudinal level displacement between adjacent samples. Approximation in FIG. 2 is based on a relationship of subsequent Expression 3. That is to say, generally in the track displacement data 56 c, Δy is several mm at most, and x is a value clearly larger than Δy (for example, 25 cm). Thus, a relationship of subsequent Expression 3 is established.

Δy²<<x²   [Expression 3]

It is sufficient that the index value is a value corresponding to the length of the track 10 caused by the displacement of the track 10 in the evaluation target section. Thus, it is not necessary for the processing of calculating the index value to include the processing of acquiring the waveform length itself of the displacement of the track 10.

For example, the processing of calculating the index value may include processing of obtaining a total sum of an absolute value of a change amount of the track 10 in the evaluation target section based on the track displacement data 56 c. For example, the processing of calculating the index value may include processing of obtaining a total sum of an absolute value of y (absolute value of a longitudinal level displacement value of each sample) based on the track displacement data 56 c. The total sum of the absolute value of y of each sample is equivalent to the waveform length L approximately calculated by the total sum of Δy/2x between the adjacent samples as described above. Thus, it is considered that the track condition can be appropriately evaluated by the evaluation value which is hardly varied corresponding to the total sum of the absolute value of the change amount of the track 10 in the evaluation targe section. The total sum of the absolute value of the change amount of the track 10 in the evaluation target section is obtained in this manner, thus the value corresponding to the length of the track 10 caused by the displacement of the track 10 in the evaluation target section can be simply calculated.

The evaluation target section is a section in which the track 10 is divided into the plurality of sections at regular intervals, thus the state of each section can be monitored by the unified index value.

The track condition display image 59A is displayed in the display device 59, thus the user can confirm the track condition. Accordingly, the user can easily consider presence or absence of the maintenance or plan the maintenance.

After the processing of Step S7 described above, each processing indicated in the flow chart in FIG. 9 may performed.

Firstly, necessity of consideration of the maintenance is determined in Step S11. The necessity of consideration of the maintenance is determined by comparing the calculated index value with a preset reference value. For example, it is indicated that as the index value increases, the track displacement increases, thus it is also applicable that the index value and the preset reference value are compared, and when the index value exceeds the reference value or is equal to or larger than the reference value, it is determined that consideration of maintenance is necessary. The plurality of reference values may be set in accordance with a degree of necessity of consideration of the maintenance. It is also applicable that when the index value exceeds a first reference value or is equal or larger than the first reference value, consideration of the maintenance is lightly prompted, and when the index value exceeds a second reference value larger than the first reference value or is equal to or larger than the second reference value, consideration of the maintenance is strongly prompted.

In subsequent Step S12, an index value in the future is predicated based on change of the index which has been acquired in the past. For example, as illustrated in FIG. 10 , tendency of the index value with respect to the elapsed time is grasped based on the data measured thus far. The index value in the future is predicted based on the tendency. For example, an approximated value f (approximated straight line or approximated curved line is applicable) is obtained based on measurement data thus far, for example. The approximated line f may be obtained by a least-squares method, for example. The index value in the future can be predicated by the approximated line f.

In next Step S13, a maintenance prediction time is predicted. As described above, the index value in the future can be predicated by the approximated line f described above. For example, it is assumed that the first reference value and the second reference value are previously set (refer to FIG. 10 ). Then, when the index value predicted by the approximated line f is equal to or larger the first reference value, a maintenance suggestion (level 1) is determined. When the index value predicted by the approximated line f is equal to or larger the second reference value, a maintenance suggestion (level 2) prompting a stronger consideration than the maintenance suggestion (level 1) is determined. A time at which the approximated line f and a straight line indicating the first reference value intersect with each other is a prediction time as the maintenance suggestion (level 1), and a time at which the approximated line f and a straight line indicating the second reference value intersect with each other is a prediction time as the maintenance suggestion (level 2).

In subsequent Step S14, maintenance suggestion information in which the track condition is associated with a track route diagram and prediction information are displayed as a track condition display image. For example, a track condition display image 59B illustrated in an upper half of FIG. 1 includes maintenance suggestion information 59B2 in which a track condition is associated with a track route diagram 59B1. The track route diagram 59B1 is a diagram in which an actual route of the track 10 is simplified and illustrated. An illustration indicating a position of a station may be added to the track route diagram 59B1. Maintenance suggestion information 59B2 determined in Step S11 described above is indicated in the track route diagram 59B1. Herein, the track route diagram 59B1 is displayed by a combination of segments divided into a plurality of evaluation target sections. Some or all of each segment is displayed as the maintenance suggestion information 59B2 distinguishable by visual recognition in accordance with the track condition. For example, a segment determined to be the maintenance suggestion (level 1) in Step S11 is colored with yellow (refer to a segment assigned with oblique lines in FIG. 11 ). A segment corresponding to the evaluation target section on which the maintenance suggestion (level 2) is determined to be necessary to be performed in Step S11 may also be displayed to be distinguished from the other segment in the similar manner. For example, the segment may be colored with red (refer to a segment assigned with a cross hatching on a lower side of FIG. 11 ). The track condition may be displayed in various types of visually distinguishable display. For example, the track condition may be displayed by a color, a pattern, a character, or a number, or may also be distinguished by a combination thereof.

A track condition display image 59C illustrated on a lower half of FIG. 11 includes prediction information 59C2. The prediction information 59C2 is an image indicating prediction information of an index value in the future, and is also an image indicating a track condition predicted in the future. The prediction information may be a predicted value of an index value, or may also be maintenance suggestion information of a track estimated from prediction information of the index value. FIG. 11 illustrates a track route diagram 59C1 after an elapse of a predetermined period (for example, after X years) on a lower side of the track route diagram 59B1 on an upper side indicating a current track condition. The track route diagram 59C1 is expressed by a segment corresponding to a plurality of evaluation target sections in the manner similar to the track route diagram 59B1 described above, and some or all of each segment indicates the prediction information 59C2 of each evaluation target section after an elapse of a predetermined period. For example, in Step S13, it is predicted that the maintenance suggestion (level 1 or level 2) is necessary in the future after an elapse of a predetermined period in some evaluation target section. The prediction information 59C2 of the corresponding evaluation target section after the elapse of the predetermined period is displayed as the prediction information 59C2 based on this predicted result. This prediction information 59C2 can be grasped as an example of a prediction of necessity of the maintenance suggestion (level 1 or level 2) in the future, that is to say, an example of the maintenance suggestion information. The predicted result is displayed to be visually recognized as the visually-recognized prediction information 59C2 in the manner similar to the maintenance suggestion information 59B2 described above for some or all of each segment.

In subsequent Step S15, presence or absence of an instruction of a detailed display is determined. The instruction of the detailed display may be performed by providing an instruction for a certain segment in the screen of the display device 59, for example. The instruction to a certain segment may be performed by a click operation, a double click operation, a tap operation on the segment, or a combination of any of those operations and an instruction of a detailed display indicated by a pull-down menu via the input unit 58, for example. When the instruction of the detailed display is performed on any segment, the processing proceeds to Step S16, and when there is no instruction of the detailed display, Step S16 is omitted, and the processing relating to the display is finished.

In Step S16, the track condition is displayed in detail on the segment on which the instruction of the detailed display has been performed. For example, as illustrated in FIG. 12 , a speed balloon is drawn from a segment selected in the track route diagram 59B1. A track condition display image 59D including a graph indicating a change of an evaluation value with respect to the elapsed time is displayed as an example of the track condition display image 59D in the speech balloon. Not only the evaluation value based on measured data but also prediction information (approximated line f) is drawn in the track condition display image 59D. Also drawn is a first reference value, a second reference value, a region of the first reference value (region determined to be a maintenance suggestion level 1), and a region of the second reference value (region determined to be a maintenance suggestion level 2). Furthermore, a maintenance consideration prediction time (for example, after a months) reaching the first reference value from the prediction information (approximated line f) and a maintenance consideration prediction time (for example, after b years) reaching the second reference value, for example, are drawn. These maintenance consideration prediction times are one example of maintenance suggestion information prompting consideration of maintenance based on a preset reference value for the index value.

Subsequently, the processing relating to the display is finished.

According to the modification example, necessity of consideration of the maintenance is easily determined by comparing the index value with the reference value.

The image with which the track condition is associated is displayed in the track route diagrams 59B1 and 59C1, thus the user can easily distinguish each evaluation target section and grasp the track condition.

The track condition display images 59B, 59C, and 59D include maintenance suggestion information prompting consideration of maintenance based on a preset reference value for the index value. Thus, the user can consider a schedule of the maintenance to determine whether or not to perform the maintenance at an appropriate timing by seeing the maintenance suggestion information.

The track condition display images 59A and 59D include the image indicating the change of the index value with respect to the elapsed time, thus the user can easily predict a timing at which the maintenance is needed.

The track condition display images 59C and 59D include an image indicating prediction information of an index value in the future. Herein, presence or absence of the maintenance suggestion after an elapse of a predetermined period is displayed in the track condition display image 59B. A line predicting the index value (approximated line f) and a line indicating the reference value are displayed in the track condition display image 59D. Thus, the user can easily predict a timing at which the maintenance of the track is needed.

Furthermore, the maintenance consideration prediction time at which consideration of maintenance of the track 10 in the future is required is predicted based on a change of the index value in the past, and the image indicating the maintenance consideration prediction time is displayed in the track condition display image 59D. Thus, the user can easily grasp the timing at which consideration of maintenance of the track is needed by seeing the maintenance consideration prediction time. The maintenance consideration prediction time may be grasped per any unit time, thus may be grasped per unit time, per unit date, or per unit month, for example.

In the example of the embodiment described above, the position-related information acquisition unit 32 and the track displacement position acquisition unit 40 are provided to the railroad car 20, and the track condition monitoring device 50 is provided to the base station, however, the arrangement positions thereof are not limited to the examples described above. The track condition monitoring device 50 may be provided to the same the railroad car 20 in addition to the position-related information acquisition unit 32 and the track displacement position acquisition unit 40, for example.

Each configuration described in the above-mentioned embodiments and each modification example can be combined with each other as appropriate unless any contradiction occurs.

The present specification and the drawings disclose aspects described hereinafter.

When the track condition monitoring device described in the section of means to solve the problem is a first aspect, a second aspect is the track condition monitoring device according to the first aspect, wherein processing of calculating the index value includes processing of calculating a waveform length of the track displacement in the evaluation target section based on the track displacement data. In this case, the index value is easily calculated by calculating the waveform length of the track displacement in the evaluation target section.

A third aspect is the track condition monitoring device according to the second aspect, wherein processing of calculating the index value includes processing of subtracting a length Li of the track from the waveform length. In this case, the user can easily imagine a degree of change of an actual track from a track by the value obtained by subtracting the length Li of the track from the waveform length.

A fourth aspect is the track condition monitoring device according to the first aspect, wherein processing of calculating the index value includes processing of obtaining a total sum of an absolute value of a change amount of the track in the evaluation target section based on the track displacement data. In this case, the total sum of the absolute value of the change amount of the track in the evaluation target section is obtained, thus the value corresponding to the length of the track caused by the track displacement in the evaluation target section is easily calculated.

A fifth aspect is the track condition monitoring device according to any one of the first to fourth aspects, wherein the track displacement data is data in which a longitudinal level displacement position of the track is associated with a position of the track in a longitudinal direction, and the processing unit calculates a value corresponding to a length of the track caused by a longitudinal level displacement of the track in an evaluation target section as an index value indicating a state of a track based on the track displacement data. Accordingly, the state of the longitudinal level displacement of the track easily having influence on the vertical vibration of the railroad car is properly evaluated.

A sixth aspect is the track condition monitoring device according to any one of the first to fifth aspects, wherein the processing unit determines necessity of consideration of maintenance by comparing the index value with a preset reference value. Necessity of consideration of the maintenance is easily determined by comparing the index value with the reference value.

A seventh aspect is the track condition monitoring device according to any one of the first to sixth aspects, further comprising a display device, wherein the processing unit displays a track condition display image indicating a state of the track in the display device based on the index value which has been calculated. In this case, the user can confirm the track condition by seeing the display device.

An eighth aspect is the track condition monitoring device according to the seventh aspect, wherein the track condition display image includes an image indicating a change of the index value with respect to an elapsed time. Accordingly, the user can easily predict a timing at which the maintenance of the track is needed by seeing the change of the index value with respect to the elapsed time.

A ninth aspect is the track condition monitoring device according to the seventh or eighth aspect, wherein the track condition display image includes an image in which the state of the track is associated with a route diagram of the track. Accordingly, the user can distinguish the position in the route diagram of the track to visually recognize the track condition.

A tenth aspect is the track condition monitoring device according to any one of the seventh to ninth aspects, wherein the track condition display image includes an image indicating maintenance suggestion information prompting consideration of maintenance based on a preset reference value for the index value. Accordingly, the user can consider the maintenance at an appropriate timing by seeing the maintenance suggestion information.

An eleventh aspect is the track condition monitoring device according to any one of the seventh to tenth aspects, wherein the processing unit predicts the index value in a future based on a change of the index value in a past, and the track condition display image includes an image indicating prediction information of the index value in a future. Accordingly, the user can easily predict a timing at which the maintenance of the track is needed by seeing the image indicating prediction of the index value.

A twelfth aspect is the track condition monitoring device according to any one of the seventh to eleventh aspects, wherein the processing unit predicts a maintenance consideration prediction time at which consideration of maintenance of the track in a future is required, and the track condition display image includes an image indicating the maintenance consideration prediction time. Accordingly, the user can easily grasp a timing at which the consideration of maintenance of the track is needed by seeing the image indicating prediction of the index value.

A thirteenth aspect is the track condition monitoring device according to any one of the first to twelfth aspects, comprising a storage unit storing plural pieces of track displacement data each detected in a time different from each other, wherein the processing unit calculates the plurality of index values based on the plural pieces of track displacement data. In this case, the plurality of index values are calculated based on the plural pieces of track displacement data each detected in the time different from each other, thus the change of the track condition can be easily grasped.

A fourteenth aspect is the track condition monitoring device according to any one of the first to thirteenth aspects, wherein the evaluation target section is a section in which the track is divided into a plurality of sections at regular intervals. Accordingly, the track is sectioned at regular intervals, and a state of each section can be monitored by an appropriate index value.

When the track condition monitoring system described in the section of means to solve the problem is a fifteenth aspect, a sixteenth aspect is the track condition monitoring system according to the fifteenth aspect, wherein the track condition monitoring device is provided to a management base, and an acquisition result by the position-related information acquisition unit and an acquisition result by the track displacement position acquisition unit are transmitted to the track condition monitoring device via a communication network. Accordingly, the track condition is monitored in the track condition monitoring device located away from the railroad car.

When the track condition monitoring method described in the section of means to solve the problem is a seventeenth aspect, an eighteenth aspect is a track condition monitoring method according to the seventh aspect, wherein calculation processing (b) of calculating the index value includes processing of calculating a waveform length of the track displacement in the evaluation target section based on the track displacement data. Accordingly, the index value is simply calculated by calculating the waveform length of the track displacement in the evaluation target section.

A nineteenth aspect is the track condition monitoring method according to the seventeenth or eighteenth aspect, comprising: (c) determining necessity of consideration of maintenance based on the index value and a preset reference value; and (d) displaying maintenance suggestion information suggesting consideration of maintenance in a display unit when it is determined that consideration of maintenance is necessary. Accordingly, the maintenance can be considered based on the maintenance suggestion information.

A twentieth aspect is the track condition monitoring method according to any one of the seventeenth to nineteenth aspects, comprising: calculating the plurality of index values based on plural pieces of track displacement data in times different from each other in the calculation processing (b) of calculating the index value; (e) predicting the index value in a future based on the plurality of index values; and (f) displaying information based on the index value which has been predicted in a display unit. Accordingly, a future maintenance plan is generated based on the predicted index value.

The foregoing description is in all aspects illustrative and does not restrict the present disclosure. It is understood that numerous unillustrated modifications can be devised without departing from the scope of the present disclosure.

EXPLANATION OF REFERENCE SIGNS

10 track 12 rail 14 management base 16 communication network 20 railroad car 27 acquisition data 28 communication device 30 track condition monitoring system 32 position-related information acquisition unit 32 a speed sensor 40 position acquisition unit 42 gyro sensor 44 distance sensor 50 track condition monitoring device 52 processor 54 communication device 56 storage device 56 a program 56 b collection data 56 c track displacement data 56 d index data 59 display device 59A, 59B, 59C, 59D track condition display image 59B1, 59C1 track route diagram 59B2 maintenance suggestion information 59C2 prediction information (maintenance suggestion information) L waveform length f approximated line 

1. A track condition monitoring device monitoring a state of a track, the track condition monitoring device comprising: processing circuitry configured to acquire track displacement data which includes first data associated with second data, the first data indicating a position of the track displaced by a track displacement, and the second data indicating a longitudinal level of the track displacement at the position; and calculate an index value indicating the state of the track in an evaluation target section of the track based on the track displacement data, wherein the position is in the evaluation target section of the track.
 2. The track condition monitoring device according to claim 1, wherein the processing circuitry calculates the index value by calculating a waveform length of the track displacement in the evaluation target section based on the track displacement data.
 3. The track condition monitoring device according to claim 2, wherein the processing circuitry calculates the index value by subtracting a first length of the track from the waveform length, the first length being a length of the track having no track displacement.
 4. The track condition monitoring device according to claim 1, wherein the processing circuitry is further configured to obtain a total sum of an absolute value of a change amount of the track in the evaluation target section based on the track displacement data.
 5. The track condition monitoring device according to claim 1, wherein the processing circuitry calculates a value, corresponding to a length of the track caused by the longitudinal level displacement of the track in the evaluation target section, as the index value.
 6. The track condition monitoring device according to claim 1, wherein the processing circuitry is further configured to determine whether consideration of maintenance of the track is necessary by comparing the index value with a preset reference value.
 7. The track condition monitoring device according to claim 1, further comprising: a display, wherein the processing circuitry is further configured to generate, based on the index value, a track condition display image indicating a state of the track; and control the display to display the track condition display image.
 8. The track condition monitoring device according to claim 7, wherein the track condition display image includes an image indicating a change of the index value with respect to an elapsed time.
 9. The track condition monitoring device according to claim 7, wherein the track condition display image includes an image in which the state of the track is associated with a route diagram of the track.
 10. The track condition monitoring device according to claim 7, wherein the track condition display image includes an image indicating maintenance suggestion information prompting, the maintenance suggestion information indicating whether maintenance is needed, and the maintenance suggestion information being based on the index value and a preset reference value.
 11. The track condition monitoring device according to claim 7, wherein the processing circuitry is further configured to predict the index value in a future period of time based on a change of the index value in a previous period of time, and the track condition display image includes an image indicating prediction information of the index value in the future.
 12. The track condition monitoring device according to claim 7, wherein the processing circuitry is further configured to predict a maintenance consideration prediction time at which consideration of maintenance of the track in a future period of time is required, and the track condition display image includes an image indicating the maintenance consideration prediction time.
 13. The track condition monitoring device according to claim 1, comprising: a storage storing plural pieces of track displacement data, each piece of track displacement data having been detected at a different time, wherein the processing circuitry is further configured to calculate a plurality of index values based on the plural pieces of track displacement data.
 14. The track condition monitoring device according to claim 1, wherein the evaluation target section is a section of the track divided into a plurality of sections at regular intervals.
 15. A track condition monitoring system, comprising: the track condition monitoring device according to claim 1; a first sensor provided to a railroad car, the first sensor acquiring track position data that specifies a position of the track in a longitudinal direction; and a second sensor provided to the railroad car, the second sensor acquiring a displacement position of the track caused by the track displacement.
 16. The track condition monitoring system according to claim 15, wherein the first sensor transmits the track position data to the track condition monitoring device, and the second sensor transmits the displacement position to the track condition monitoring device.
 17. A track condition monitoring method of monitoring a state of a track, the track condition monitoring method comprising: acquiring track displacement data which includes first data associated with second data, the first data indicating a position of the track displaced by track displacement, and the second data indicating a longitudinal direction of the track displacement at the position; and calculating an index value indicating the state of the track in an evaluation target section of the track based on the track displacement data, wherein the position is in the evaluation target section of the track.
 18. The track condition monitoring method according to claim 17, wherein the calculating the index value includes calculating a waveform length of the track displacement in the evaluation target section based on the track displacement data.
 19. The track condition monitoring method according to claim 17, further comprising: determining whether consideration of maintenance of the track is necessary based on the index value and a preset reference value; and displaying, via a display when the determining indicates that consideration of maintenance is necessary, maintenance suggestion information suggesting the consideration of maintenance.
 20. The track condition monitoring method according to claim 17, wherein the calculating includes calculating a plurality of index values based on plural pieces of track displacement data, wherein each piece of track displacement data is detected at a different time, the plurality of index values including the index value; predicting a future index value at a future time based on the plurality of index values; and displaying information based on the future index value. 